P0870 OBD II Trouble Code Transmission Fluid Pressure Sensor / Switch C Circuit
How to diagnose, repair, and info on causes of a P0870 transmission trouble code related to the trans fluid pressure sensor switch C circuit. Also includes links to relevant forum topics on the code.
Symptoms of P0870 OBD II Trouble Code
- Malfunction Indicator Light On
- Change in shift quality
- Vehicle starts off in 2nd or 3rd gear (limp in mode)
Common Causes of P0870 OBD II Trouble Code
- Open in the signal circuit to the TFPS sensor - possible
- Short to voltage in the signal circuit to the TFPS sensor - possible
- Short to ground in the signal circuit to the TFPS sensor - possible
- Failed TFPS Sensor ? likely Internal mechanical transmission issue - possible
- Failed PCM - unlikely (programming required after replacement)
Severity of P0870 OBD II Trouble Code
Severity depends upon which circuit the failure has occurred in. Since this is an electrical failure, the PCM/TCM can compensate to some degree. The failure may mean that the PCM/TCM modifies the shifting of the transmission if electronically controlled.